Device for guiding thin film bands



July 12, 1949. J. A. HARINGx DEVICE FOR GUIDING THIN FILM BANDS Filed July 3, 1946 Patented July I2, 194,9

2,475,743 DEVICE FOR GUIDIN G THIN FILM BANDS Johannes Adrianus Haringx, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application July 3, 1946, Serial No. 681,390 In the Netherlands September 30, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires September 30, 1963 3 Claims.

This invention relates to a device for guiding a thin film band, for example, a very thin film made from cellophane.

The customary devices for guiding film bands which, for example, are perforated and are moved by means of toothed rollers, or sometimes are guided via an untoothed roller between two flanges, have in the case of these very thin films the drawback that the material cannot sustain it so that damage and even breakage are unavoidable. More particularly when the lm is in a damp condition, which often occurs when it is being worked up, this drawback is experienced to a high extent.

According to the invention, this drawback is obviated by compelling the film band at the place of the guiding member to engage a stop by one of its sides by driving and/or braking the said band to a greater degree on one side thereof with respect to the longitudinal axis thereof, than on the other side thereof, said stop being located in the proximity of the guiding member. This guiding member may be a rotating or stationary roller or a stationary film track. Due to the iilmband being driven and/or braked unsymmetrically as described above, a force' couple is exerted on the film in the plane of the latter so that the film experiences a resultant lateral force and moves sideways so as to engage the stop. This lateral force can be accurately adjusted to any desired value by the choice of the forces for driving and/- ample, a few forms of construction are repre-4 sented.

Figs. 1 and 2 represent diagrammatically a bottom and a lateral view respectively, of a device in which the film is substantially braked unsymmetrically.

Fig. la represents diagrammatically a bottom view of another form of roller which may be used. l

Figs. 3 and 4 represent diagrammatically a bottom and lateral view, respectively, of a device wherein the film is braked and driven unsymmetrically.,

Figs. 5 and 6 represent diagrammatically a bottom and lateral view, respectively, of a further device in which unsymmetrical braking takes place.

In Fig. 1, I designates a film band which runs on a roller 2. In Figs. 1 and 2 this roller is a guide roller which moves along with the film. In Figs. 1, 2, 3 and 4 two small felt plates 3 and 4 are pro-A vided unsymmetrically with respect to the longitudinal axis of the film, the film band running between them. These plates may be pressed more or less strongly against one another, which pressure can be adjusted at will with the aid of a device (not shown). Due to the friction between these plates and the film band, a resultant force is exerted on the film in the plane of the latter, so that the film engages a stop 5. This is promoted, for example. by the fact that the film is not supported throughout the whole width by the roller 2 (cf. Fig. la) which results in itself already in a more or less unsymmetrical drive.

With the device according to Figs. 3 and 4 the said resultant force is further increased owing to the film being also unsymmetrically driven, for the roller 2 is here a driving roller, whilst a pressure roller 6. which engages unsymmetrically only part of the driving roller 2 in the axial direction, ensures that the .film cannot slip at this point. This results in that an additional force is exerted on the film unsymmetrically with respect to the axis of the latter, which force moves the film forward. If the pressure exerted by the lm on the stop is still so great that the film curls up on its side and thus still forms a foot, it is advisable to provide the stop in such a manner that the film always engages the latter with its curved portion, as is shown in Figs. 3 and 4.

Figs. 5 and 6 show another possible embodiment of the invention. Here the film is guided over a piece of felt 'l cut oli obliquely. The roller may also be stationary, in which event the piece of felt 1 maybe fastened to this roller. Here again we obtain an unsymmetrical friction which compels the film to engage the stop. The latter form of construction can only be used if before the roller 2 the film band has a sufficient free length so that a smaller angular displacement is sufiicient to cause is to engage the stop since in this case the frictional force is much smaller than in the above-mentioned forms of construction and consequently the film experiences a smaller force which pushes it against the stop. In the latter form of construction the engagement of the stop by the film is favoured by the fact that the latter is compelled to slide over an oblique surface, so that. so to speak, it slides against the stop. This takes place more particularly when the iilm is moreover arranged vertically. so that also the weight of the iilm contributes thereto.

As a matter of course the invention is not confined to the above-mentioned forms of construction given, by way of example, but it also includes a device in which the lm. when guided in accordance with the invention, is simultaneously wound, for example, on a spool.

What I claim is:

1. A device for guiding a thin film band comprising a roller over which the band passes for changing the direction thereof, a stationary plate element adjacent said roller and following the contour thereof for a part of the circumference of said roller, said plate element having an edge which is transverse the direction of travel of the band cut of! obliquely with respect to the axis of said roller so that the shape of said plate element in effect diminishes in a direction toward one side of said roller and a stop located beside said roller and said plate element at said one side of said roller.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Kellogg Aug. 20, 1935 Hasbrouck, Jr Dec. 21, 1937 Number 

